The invention relates to a resistance thermometer having a measuring resistor in the form of a resistance layer consisting essentially of a metal of the platinum group in a thickness of 0.1 to 10 μm, which is deposited on an electrically insulating surface of a carrier having a thermal expansion coefficient in the range of 8.5 to 10.5×10−6/° K and is provided with an electrically insulating cover layer.
German Patent DE 195 40 194 C1 discloses a resistance thermometer in which the substrate consists of magnesium titanate. The thermal expansion coefficient of magnesium titanate lies in the range of platinum. In this way, stresses are dissipated and the dimensional accuracy is improved relative to substrates made of aluminum oxide. For this purpose, however, it must be taken into account that magnesium titanate has an open-pore structure and a low fracture strength.